Now fet the Distance of the Subftile from D to T, and draw the dotted Line Z M for the Subftile, and fet the Plane's Difference of Longitude from T to B, for the Point of the Hour-Line of XII; then fet off 15° of Chords each way from B in the lower Semicircle CA, which will give the Points X X X X X, &c. draw the Border of the Dial IK perpendicular to the Subftile Z T; Laftly, by a Ruler laid from Z to the Markes X X X X, &c. you will have the Points VI, VII, VIII, &c. in the Side of the Dial IK, through which Lines, drawn parallel to the Subftile, fhall be the Hour-Lines required; and thus is the Dial finished as in the Figure.

3. Admit the fame Plane recline from the Zenith 60° oo', which is more than the Pole; then, though this Dial may be referred to a new Latitude and Declination, and fo be made on an upright Plane; yet I prefer the Method by Projection of the Sphere and reclined Plane on the Horizon of the given Latitude; and fo by referring the Interfection of the HourCircles and the Plane to the primitive Circle, the Hour-Lines may be drawn as hath been often taught in the Problems foregoing. A Figure of this Dial you have in the following Page.

PRO

To draw Hour-Lines on a North reclining Plane declining Eaft or Weft.

Practice.

1. Admit a North Plane decline to the West 35° co', and recline from the Zenith of London 18° 30'. This Dial may be made either by Projection of the Sphere and reclining Plane on the Horizon of London; or by Calculation or laftly, by finding the new Latitude and Declination, as hath been taught. A a á 2

VOL. II.

I have

I have given a Specimen of this Dial made by the laft Method, viz. By making an upright Dial for Latitude 29° 19′, and Declination 32° 57' being the new Latitude and Declination (as per Prob. 8,) proper to this reclining Plane.

Note, The dotted Lines make the inclining Dial of the fame Plane.

2. If the fime North Plane decline as much to the Ealt, viz. 35° col, and recline from the Zenith fo far as to pafs taro' the Interfection of the Equinoctial with the Meridian at ; then will a Dial made by Projection of the Sphere and Plane on the Horizon of London, be fuch as the following; the Truth of which

the

the young Student may prove by Calculation if he pleases.

3. In the laft Place, admit a North Plane decline 3300 Eastward, and recline from the Zenith of London 65° 00', fo as to pafs between the Interfection E and the South Point of the Horizon S.

Then by Projection of the Sphere and Plane on the Horizon of London, you have a Dial made as the following.

PRO

To find what Hour-Lines are proper to any given Plane; or to discover at what time the Sun begins, : and ceafeth to fhine thereon.

Practice.

When a Perfon purposeth to make a Dial, he must first determine what Hour-Lines will fall upon the given Plane, and what will not. For by drawing more or lefs than are neceffary to the Plane, he will equally bewray his Ignorance and render himself ridiculous.

There